CN 200520075293 U disclosed a known electrical connector having a spring formed of a bent metal rod of circular cross section. However, due to such a design, the spring of the known connector is sensitive for variations in the diameter of the plug. In other words, the spring force exerted on the plug for holding the same in place may vary and be insufficient dependent on the tolerance allowed for the plug and/or wear of the plug due to multiple plug-in and plug-out operations.